The gravity-driven starting jet characteristics over the range of Reynolds numbers from 1179 to 10 611 have been investigated using planar laser induced fluorescence and particle image velocimetry. Of the 17 cases investigated, pinch off for the leading vortex was found to appear at Reynolds number above 3000. For those cases involving pinch off, limiting values for the nondimensional circulation for the leading vortex could be identified at around 1.26 and the nondimensional energy was at about 0.35 ± 0.01, respectively. The former agrees with the universal value proposed by Shusser et al. [Phys. Fluids 18, 033601 (2006)] to within 9%, while the latter lies within the analytical result range (from 0.27 to 0.4) proposed by Gharib et al. [J. Fluid Mech. 360, 121 (1998)]. The results thus suggested that the pinched-off vortex ring would achieve similar characteristics and that may also be independent of the generation mechanism. © 2008 American Institute of Physics.
ASJC Scopus subject areas
- Condensed Matter Physics